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1. Field of the Invention
This invention relates generally to lift mechanisms for a personal mobility vehicle (PMV) and more particularly to a lift for a PMV which is attachable to a class II or Class III trailer hitch attached to the rear of a vehicle.
2. Description of Prior Art
The popularity of self-propelled personal mobility vehicles (PMV) for use by the physically challenged is gaining in popularity. These PMV""s are typically of a three or four wheeled design and are used by those physically challenged who are either able to ambulate short distances or who travel with a personal attendant able to assist in the loading and offloading of a PMV from a car trunk or a rear door of a van thus facilitating access by the physically challenged person during PMV use and storage.
Several patented prior art systems and apparatus for the storage and conveyance of a PMV when not in use are disclosed in the following prior U.S. patents:
U.S. Pat. No. 6,007,289 to Kruse, et al.
U.S. Pat. No. 5,114,120 to Bartelt, et al.
U.S. Pat. No. 4,741,660 to Kent
U.S. Pat. No. 4,705,448 to Mungons
U.S. Pat. No. 5,011,361 to Peterson
U.S. Pat. No. 5,8616,763 to Hamann et al.
U.S. Pat. No. 5,431,522 to Ross
U.S. Pat. No. 4,127,200 to Mann
U.S. Pat. No. 4,671,729 to McFarland
U.S. Pat. No. 6,386,410 to Van Dusen et al.
U.S. Pat. No. 4,697,975 to Lippold
U.S. Pat. No. 4,738,581 to Kuhlman
U.S. Pat. No. 5,752,799 to Carey et al.
U.S. Pat. No. 5,853,282 to Bechler et al.
U.S. Pat. No. 5,810,547 to Bruno et al.
U.S. Pat. No. 5,205,700 to Lin et al.
U.S. Pat. No. 5,431,526 to Peterson et al.
Of particular interest in these prior art devices, the invention taught by Bartelt in U.S. Pat. No. 5,114,120 teaches an equipment mounting system which supportively engages with and depends upon support from a class II or class III trailer hitch attached to the back of the vehicle. These class II and class III trailer hitches typically provide a rectangular elongated cavity for receiving a closesly similarly configured tongue of a trailer hitch. This equipment mounting system includes a pivotal leg which extends laterally beyond the right side of the vehicle for deployment and pick up of equipment stored at the rear of the vehicle on this system.
Another notable prior art U.S. Pat. No. 6,007,289 invented by Kruse teaches a wheelchair lift which is also attached to the rear trailer hitch structure attached to the rear of a vehicle. In this PMV lift, a lift support assembly is provided at the lower end of the upright stanchion so that a PMV may be loaded and offloaded onto a ground or sidewalk or road surface which is adjacent to and outboard from the side of the vehicle.
In depending upon the trailer hitch devices attached to the rear of such a conveyance vehicle, sufficient strength for lifting a PMV becomes an issue. The further from the center line of the vehicle and thus the trailer hitch mechanism that a PMV being lifted from or into the rear of the vehicle gets, the greater the torsional load being placed on the rectangular cavity and the trailer hitch itself. In the Bartelt disclosure, the equipment appears to be of relatively light weight nature, while the Kruse teaching depends for added strength upon this lift support assembly 26 to allow the apparatus to deploy and lift a PMV onto and from a surface which is substantially outboard or laterally disposed from the right side of the vehicle.
In the present invention, this load bearing limitation between the PMV lift and the trailer hitch itself is dealt with by strictly limiting the arch or rotational movement of the lifting boom about the upright axis of the stanchion so that no movement is permitted beyond a plane lying fore and aft to the vehicle and passing through the upright stanchion of the PMV lift itself.
This invention is directed to a personal mobility vehicle (PMV) lift for loading and offloading a personal mobility vehicle (PMV) into and from a rear portion of a vehicle, the vehicle having an interior floor and a trailer hitch rigidly attached to the rear of the vehicle to which the PMV lift is rigidly engageable. The PMV lift receives substantially all of its support from the trailer hitch and includes an elongated laterally extending lifting boom and a drive mechanism connected adjacent a proximal end thereof. The drive mechanism includes an elongated flexible lifting cable or belt which is operably connectable for raising and lowering the PMV by operation of the drive mechanism. An upright stanchion is supportively connected to the lifting boom while an elongated lift support arm is supportively connected to a lower end of the stanchion. A trailer hitch engaging member is connectable at one end to the trailer hitch, the other end of which is connected to and supports a proximal end of the lift support arm. The PMV lift and PMV are substantially supported entirely by the trailer hitch.
It is therefore an object of this invention to provide a PMV lift for loading and offloading a PMV into and from the rear portion of a vehicle by utilizing as a sole support for the PMV lift and PMV a class II or class III trailer hitch having a rectangular receiving cavity longitudinally disposed there through.
Still another object of this invention is to provide a PMV lift which solely depends upon the interengaging structure with a class II or class III trailer hitch for its support and which limits the amount of stress placed on the trailer hitch by preventing actuate movement of the lifting boom from exceeding a predetermined distance from the center line of the vehicle and the trailer hitch itself.
In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with reference to the accompanying drawings.